Question

Will give medal for explanation. x2 − 16x + ____

Answer 1

Are you trying to find the blank?

Answer 2

yeah, sorry for not clarifying.

Answer 3

No that is fine, well the third number can varry.

Answer 4

1 was thinking -16 but 1 don't know.

Answer 5

This form is called quadratic form. Are you trying to change it vertex fom?

Answer 6

vertex form?

Answer 7

yes ? do you know what it is ?

Answer 8

no

Answer 9

http://static.prometheanplanet.com/images/resources/resource-thumbnails/thumb-nalg2-05-01-0025-diagram-thumb-lg-png.png

see this, I am trying to see if it is possible to solve this question using vertex form. However you need to know the third number.

Answer 10

1 don't think that's what 1'm supposed to do...

Answer 11

1'm doing perfect square trinomials

Answer 12

ok let me see

Answer 13

I solved it, but by guessing and using some common sense. Just tell me is this the thing you are looking for x^2+16x+?

Answer 14

yes

Answer 15

ok well I did it like this:

\[x^2+16x+?\]
\[(x+?)(x+?)\]

Answer 16

okay

Answer 17

I told myself x times x is x^2, so ? has to be something to equal 16x

Answer 18

what times x gives 16x ?

Answer 19

16

Answer 20

ok let's plug it in and see if it is right ?
\[\left( x+16 \right)\left( x+16 \right)\]

Answer 21

x^2 + 32x+ 256???!??!!!

Answer 22

Wow no that is not what we want. we want 16x right?

Answer 23

yeah

Answer 24

wouldn't it be -16?

Answer 25

No, but think of a number lower than 16

Answer 26

8?

Answer 27

Lets plug it in.

Answer 28

\[(x+8)(x+8)\]

x^2 + 16x + 64

Wow the third number is 64!!!

Answer 29

Awsome you did good man!

Answer 30

but it's x^2 - 16x

Answer 31

would it still apply?

Answer 32

no we have to change something

Answer 33

Third number is there.

Answer 34

but it needs to be x^2 − 16x + ____

Answer 35

the third number is positive

Answer 36

If you liked my answer, give me a medal, and I would appreciate if you write me a fan testimonial as well. If you need more help, let me know to clarify it for you. :)

Answer 37

I am sorry (x-8)(x-8) is X^2 - 16x + 64

-8 times -8 is 64. See you are smart ! awsome. :D

Answer 38

okay thanks.

Answer 39

Your welcome!